Mobile subscribers are frequently interrupted by “spam” calls from unknown persons that not only waste time but can also lead to excessive charges on the subscriber's phone bill. These unsolicited calls may come from telemarketing companies, robots (unsolicited calls being in such case sometimes referred to “robocalls”), fraudsters, and aggressive sales organisations. Sometimes the call is simply to sell a new service, encourage the subscriber to make a claim against a third party, but can also be an inducement to call back a number that has premium rate charges associated with it.
Calls can be blocked afterwards on most phones, but this means that the subscriber has to accept the call and determine for himself or herself whether the caller is legitimate or not. In some cases, a subscriber can receive many such calls a day and may have to eventually resort to keeping their phone on silent mode so as to not be disturbed or in the extreme obtaining a new MSISDN, both of which are inconvenient and can lead to missing important calls.
There is therefore a need for a method to assist users in avoiding the drawbacks of undesired calls.